胰岛FasL基因转染对大鼠胰岛移植的影响

The effect of FasL gene transfer to islet cells on pancreatic islet allografts

目的 探究胰岛细胞FasL基因转染对同种大鼠胰岛移植的影响。方法 通过磷酸钙沉淀法构建含目的基因FasL的重组腺病毒AdV-FasL,感染胰岛细胞后移植于糖尿病受者大鼠,通过RT-PCR和免疫组织化学检测移植物FasL表达,观察移植物存活情况及基因转染胰岛细胞凋亡情况。结果 单纯移植胰岛组平均存活期为（6.3±0.56）d,FasL基因转染组并未出现排斥延迟,反而排斥加速,存活期缩短至（3.4±0.24）d。FasL转染的胰岛细胞在移植后24h见FasL表达,在 48 h表达增强,AdV-5感染组及未转染组未见FasL表达。TUNEL标记见移植后FasL转染胰岛细胞凋亡。结论 尽管表达FasL的睾丸细胞与胰岛共移植可诱导活化的淋巴细胞凋亡,使胰岛移植物获得免疫豁免、存活期延长,但通过FasL基因转染使胰岛细胞直接表达FasL,引起胰岛细胞凋亡和粒细胞浸润,导致排斥加速。

To investigate the effect of FasL gene transfer to islet cells on pancreatic islet allografts. Methods A recombinant and replication-deficient type-5 adenovirus encoding murine FasL (AdV-FasL) was constructed by the method of calcium phosphate precipitation. The pancreatic islets were infected with the recombinant adenovirus AdV-FasL and transplanted into diabetic recipients. FasL expression was detected by RT-PCR and immunohistochemistry methods. Allografts survival and the apoptosis of gene transferred islet allografts were analyzed. Results All animals receiving islet allograft alone returned to a diabetic state by several days, mean survival time (6. 3±0. 56) days. Compared with the control group, no delay of rejection and prolongation of allografts survival were observed in the group of FasL gene transfer. The rejection was accelerated and the allografts survival was shortened to (3.4±0.24) days (P < 0. 05). Pancreatic islets infected with AdV-FasL demonstrated positive staining for FasL at 24 h, with increased intensity at 48 h, but not in AdV-5 infected or uninfected islets. TUNEL labeling of pancreatic islet allografts at 24, 48 h revealed apoptosis that was not in AdV-5 infected allografts. Conclusion Though co-transplantation of FasL-expressing testicular cells can induce privilege of islet allografts and prolong allografts survival, direct expression of FasL on islet allografts infected with AdV-FasL accelerated the islets rejection by islets apoptosis and granulocytes infiltration.